Comparison of the responses of Mycobacterium tuberculosis and Mycobacterium bovis to nutrient starvation

Transcriptional profiling of Mycobacterium tuberculosis H37Rv and Mycobacterium bovis Ravenel before (i.e., log-phase control) and at 24h and 96h after nutrient starvation. The transcriptional profile of the two strains were compared at log phase, and after 24h and 96h of starvation. In addition, the response of each strain to starvation was examined after 24h and 96h of starvation. For examination of the responses of each of the two strains to starvation 6 biological replicates were used and each log phase control (i.e., 6 for each strain) was compared to the starvation samples (i.e., at both 24h and 96h after starvation). This resulted in 24 comparisons (i.e., 12 for each strain). For comparison of the two strains at each of the 3 time points (i.e., at log-phase, 24h and 96h after starvation) 4 biological replicates of one strain (M.tuberculosis H37Rv) were compared to 6 biological replicates of the other strain (M. bovis Ravenel). This involved a first experiment in which samples from 2 independent cultures of H37Rv were compared to 4 independent cultures of Ravenel (i.e., each H37Rv replicate was compared to each of 2 Ravenel replicates), followed by a 2nd experiment in which 2 independent cultures of H37Rv were compared to 2 independent cultures of Ravenel. This resulted in 18 total comparisons.